Protos - RXJ Head and Skookum - Build Hints and Data

[povern]

I have finally gained the funds and time to change one of my Protos over to Fly Bar Less. While doing this I also decided to see how much it would change the Heli from, head speed, weight, servo draw etc. do I kept notes on all these during the change over, and decided to share these with a bunch of freaks. Please don’t expect a full build thread, but maybe a couple hints here and there. Also, I fly big sky maneuvers, not close in Humming bird on crack 3d.

Protos Setup With Flybar and without (Note Gyro Change)
Protos non Carbon Frame: Full stock Protos head with 10mm grips
SAB Mains
Gorilla Gear Paddles with Full Weights
MSH Tail Blades
9650 with MG Gears on cyclic
Mini G / 9257 – had to switch to Spartan due to wire length. Spartan is .4 of a gram lighter
CC80 / Stock Motor
Western Robotics BEC
AR7000
7S A123
Heli Direct FG Canopy

Here was the first surprise.
Weight With Flybar
RTF – Battery #8 1860 Grams
No Blades Bolts in Grips 1770 Grams
No Blades or Battery 1180 Grams

With Skookum
RTF Battery #8 1890 Grams
No Blades Bolts in Grips 1770 Grams
No Blades or Battery 1205 Grams

*All weights contain a counterweight of 15.8 grams, on the tail boom, due to running 7SA123 with the HeliDirect FG canopy.

Notice how the heli gained weight with the Flybar removed. That is due to going from a full plastic Protos head, to an all metal RJX head. I didn't expect that.

Here is a Eagle Tree Graph showing the Protos with the Fly Bar Still installed, using the setup listed above (Mini G Gyro)

Battery #7 7sA123, Cold, after fresh charge used 1662 mah, 4.5 minutes Flips Rolls some inverted flight, some backwards inv, backwards, Pitch pumps, etc.

And there is the second surprise: Max full RX amperage draw was .6amps. With only one spike over .5amp.

More too come....

[povern]

Building the RJX head is very straight foward. If you have ever built a head for a CP heli, you will have no issues.

Built RJX with stock Trex 500 parts and the feathering shft sleeve:
- Do not tighten the swash driver bolts until the head is on the shaft.
- Purchase all Trex500 parts on the parts list and then
- Purchase Trex 500 Links Part #H50054T
- Use the Align Thrust Bearings in the grips

Connecting the head to the Protos:
- Use the Protos Swash
- Put the Jesus bolt through the Middle hole on the head block
- Use the Protos rods and links from the Servos to the swash.
- From the swash to the grips:

Use MSH rods that go from the Servos to the swash: MSH51023
Use MSH Links on the swash
Use Trex 500 Links on the grips
Link should measure about 56.25 mm

One issue that I have seen with the RJX head on the Protos is the swash driver arms will hit the Protos Anit Spin bracket. You will need to tip the bracket back, but not too far. I have replaces the stock bolt, that goes through the anit spin bracket, with a longer one and added one bearing.

[povern]

I'm not going to get into what settings is best for the Skookum on the Protos, that is still a work in progress for me, I do have the heli flying great, but it still needs some fine tuning. However, the 3d default file that comes with the 360 is an excellent starting point. Instead I'm going to show you where I located everything:

If you have ever wired a Protos, you know how clean it can be and will notice right away where I ran everything. I didn't need to drill any holes in the frame for this install.



One trick I learned (Thanks Capi) is when you go to set blade pitch. Read This: https://www.helifreak.com/showthread.php?t=105820 Post #13. Really slick. That is one smart rodent.

[povern]

Battery #7, Cold, after fresh charge used 1749 mah, 4.5 minutes. Same basic type of flight as above:


As you can see, not much of a difference.

Surprise #3; The total RX draw. Max was still less then an AMP.

I also noticed that the heli has a harder time holding the head speed. Think I might drop down one tooth on the pinion (go to 14). I think with how responsive it has become, I can do with less head speed.

Here is another interesting bit of information. The two above graphs are with SAB blades. for testing and set up I was using the Helidirect 3d blades. Here is the chart for them, same information and flight as above two, only difference is the blades.



Surprise #4: The 3d Blades used 400mah more then the SAB blades.

Final Thoughts: Am I happy with the change? I haven't decided yet. Although it flips and rolls very fast and does FF (Inverted, backwards, or inv backwards) like it is on rail, the collective pop is gone. I will need to fix this. I also will be trying out LIPOs for next summer. I think a couple Hyperions and a couple Zippys will be great.

[nexgen]

can you get smaller swash driver arms for that head? or maybe use some other arms. the angles on the plastic parts to the swash look a little extreme, like they might pop off the balls at extreme swash angles.

[povern]

I have about 20 flights on this system, and have tested it. Although they seem extreme, they are actually OK.

As far as I know there are no other arms available. I may need to try some Trex 600 link arms from the swash to the grips, and then raise the head up one hole. That would help with both the angle of the swash driver, and the arms hitting the anti rotation bracket.

povern

[OverTemp]

Collective pop is gone?

Do you think the servos are unable to provide the pop (wouldn't think so with the low current draw) or there is just a setting that needs to be tweaked?

[povern]

Originally Posted by OverTemp

Collective pop is gone?

Do you think the servos are unable to provide the pop (wouldn't think so with the low current draw) or there is just a setting that needs to be tweaked?

Not the servos, remember they were on when this whole experiment started.

Believe it or not, I lowered the collective from +-13 to +-10, and a lot of the pop returned. Maybe I was bogging the motor to much????

[povern]

Originally Posted by nexgen

can you get smaller swash driver arms for that head? or maybe use some other arms. the angles on the plastic parts to the swash look a little extreme, like they might pop off the balls at extreme swash angles.

The Protos swash drivers, probably shouldn't be used. they throw the phasing off. They are also a different height then the Stock RJX ones.

In the Skookum software, needed to offset phasing by -8 degrees, degrees for the Protos swash drivers.

I have some 2mm Trex 500 ball links coming, I should be able to put these on the Protos swash and go back to the stock RJX swash drivers, should put phasing and fit back to where it needs to be.

Here is a thread going right now concerning phasing and the affect on a heli: https://www.helifreak.com/showthread.php?t=161158

Pics to come.

[OverTemp]

WARNING!!!!!!!!!!!!!!!!!!

Don't put the Align 2mm balls on the Protos swash w/o grinding a little off the end of the threaded portion!!!!!!

The threaded portion is ever so slightly longer than that the Protos balls and they actually make it through the metal into the phenolic and bind the center ball. I thought I had gotten locktite in my ball and I started taking everything back apart... as soon as I removed the TRex balls it loosened right up.

Another solution is to use JR balls with the JR swash stand-offs... same length as the protos balls but TRex diameter. No binding.

I've got mine ready to power up... for some dumb reason I'm afraid to put power on the v-bar

The whole thing feels like putting a space-ship guidance system in an AMC Pacer.

[OverTemp]

I just installed my RJX head. The swash drivers hit the swash plate at anything over 7 degrees of cyclic... this is discouraging. This is the longest build ever!

Anyone have any ideas? The only way I can see to fix it is to shorten the driver arms... gotta find a friend with a machining skills.

[CatchmyCorsair]

Originally Posted by OverTemp

... this is discouraging. This is the longest build ever!

You made it more complicated! MSH didn't design what you are doing. Building it stock it goes together smoothly.

[OverTemp]

I found a guy that can machine down the swash a bit... should fix my woes. Another week to wait for short Spektrum leads and I'm good to go.

[OverTemp]

How much collective and cyclic pitch could you get? I was limited by binding of the servo links on the frame. Did you grind out the frame a bit?

[CatchmyCorsair]

Originally Posted by OverTemp

How much collective and cyclic pitch could you get? I was limited by binding of the servo links on the frame. Did you grind out the frame a bit?

I think I'm running 12-12.5 and 8 deg. No frame grinding.

[OverTemp]

Cool. I've got mine with 10.5-11 on collective and 9 on cyclic... working good now.

Flights today were a lot of fun. It actually feels like I'm flying the sim... kinda odd.

The cool thing is that I can throw it into the biggest loop in the world and never touch the ailerons and it comes out perfectly level... same with inverted piros... it just stays level. Gonna make me lazy.

I think I still prefer the repsonsiveness of my 12S 600E w/ Vibe FB head for 3D... it jsut feels more "right now". The Vbar is nicer for the big stuff.

[povern]

I just installed my RJX head. The swash drivers hit the swash plate at anything over 7 degrees of cyclic... this is discouraging. This is the longest build ever!

I was running +-13 on collective and 8 on cyclic, with no grinding. I lost some pop on collective so I went to +-10 and got some back. Which hole do you have the jesus bolt throuhg? I'm in the middle, and going to move it to the top, this will move the swash drivers away from the antirotation bracket.

I also do not like how far the arms stick out. So I will raise the head to the highest jesus bolt hole and switch to 600 links between the swash and grips.

[povern]

WARNING!!!!!!!!!!!!!!!!!!

Don't put the Align 2mm balls on the Protos swash w/o grinding a little off the end of the threaded portion!!!!!!

Is this with the balls for the 500? I bought a set (H50093T) and there are 2 types of balls in it. One kind has a V shaped standoff, this one has shorter threads then the Protos balls. The other ball is straight from the ball to the thread, and this one is longer.

The V-Balls (?) do stick out farther then the Protos balls. so will need to test for fit and clearance.

[OverTemp]

I dunno... I sold my 500. I literally took the balls off the inner 500 swash and screwed them into the Protos swash.

I looked them up in the TRex 500 manual. It says they are M2 x 3mm balls. The Protos balls are M2 x 2.8mm. Literally a .2mm difference. I could BARELY tell when I held the two side-by-side.

I'm ordering some M2x4.8 Protos balls to use on the swash w/ 2mm nuts... should get that extra roll-rate I'm looking for.

I took all the expo out of the VBar and dialed it into the TX... seems to respond better now. This thing is sick!

[povern]

Ok, Made some changes tonight to try and get the phasing correct.

I went back to the RJX swash drivers. In order to do this, I needed to go to Trex 500 balls on two of the swash holes. I found 2 different types of balls for the Trex 500 that came with 2 mm threads. The one with the V style base could not be used due to causing the swash drivers to hit the swash. The other type, the threads were too long, they actually bound against the ball in the swash. So I just tapped the end of the threads with a dremel.

Once these were installed, I saw how close the drivers were to the swash, so I lowered my head to the lowest position.



This change allowed me to go with 0 correction on the phasing.

However, this puts the swash driver very close to the swash with maximum throws. I'm running +-10 and 8, although it does not hit, it is VERY CLOSE, I will not be able to run any more on this head.

Here is a pic at max throw.




Hopefully tomarrow I can test this change out.